The present invention relates generally to agricultural implements and, more particularly, to a marker assembly having a spring linkage that limits momentum in the marker assembly during deployment of the marker assembly from a folded, stow position to an extended, working position.
Agricultural seeders, which are commonly used to deposit seed, fertilizer, and granular chemicals onto a farm field, generally consist of a towable frame that supports one or more rows of seed units. Seed or other granular product is typically metered to the seed units which in turn deposit the product onto the farm field. The seeder will often include furrowing opening devices, such as coulters, knives, shanks, and the like that cut a furrow into the farm field immediately ahead of the seed units so that the granular product is deposited into a furrow rather than simply atop the farm field. A trailing packer will then pack the furrow to improve germination and/or fertilization.
Agricultural seeders are also commonly outfitted with a pair of marker assemblies. Each marker assembly will generally include a marker frame which carries a marking disc. A seeder will typically have a marker frame extending laterally on opposite sides of the seeder, and the marker frames can be independently raised and lowered by a respective lift assembly, such as a hydraulic cylinder. The marking disc is designed to cut a furrow into the farm field which serves as a marker as to the position of the seeder as the field was passed. Thus, during a subsequent pass of the farm field, the operator can position the seeder so that the next pass is properly aligned with the previous seeding pass to prevent overseeding of a previously seeded area or to prevent undesirable gaps in the seeded rows. Improper uniformity in spacing of the rows as well as distribution of the seed can negatively impact crop yields.
Increasingly, there is a desire for a foldable or collapsible marker assembly that can be retracted from an extended, working position to a folded position for transport and storage. One proposed foldable marker assembly has a frame consisting of a series of interconnected linkages that can pivot with respect to one another. An actuator, such as a hydraulic cylinder, may retract the linkages or extend the linkages depending upon the desired orientation for the marker assembly. One of the drawbacks of such retractable and extendable marker assemblies is that tremendous momentum can build up in the linkages as the marker frame is rapidly deployed. This momentum can result in the marking disc impacting the ground at an undesirable speed and undesirable force.
Therefore, there is a need for a marker assembly in which the momentum in the linkages can be reduced prior to engagement of the marking disc with the soil surface.